1. Field of the Invention
The present invention relates to a solid-state imaging element containing a plurality of photoelectric converting regions which are arranged on a surface of a semiconductor substrate along a row direction and a column direction perpendicular to this row direction, and also related to a digital camera using the solid-state imaging element.
2. Description of the Related Art
In solid-state imaging elements used in digital still cameras, electron charges which correspond to image signals are detected by photoelectric converting elements such as photodiodes. As a result, generally speaking, it is practically difficult to widen dynamic ranges of these solid-state imaging elements. To solve this difficulty, such a process operation has been employed so as to acquire wide dynamic ranges. In this process operation, while both a high-sensitivity photographing operation and a low-sensitivity photographing operation are continuously carried out within a short time, two sheets of acquired image signals are synthesized with each other (refer to, for instance, Japanese Laid-open Patent Application No. 2001-94999). However, since these two image signals to be synthesized with each other do not correspond to such two image signals which have been acquired at the same time, there is a problem that unnatural images may be produced as to a motional photographic subject.
As another solving means, the use of such a solid-state imaging element has been proposed (refer to, for example, Japanese Laid-open Patent Application No. 2001-8104). This solid-state imaging element owns a photoelectric converting element having a relatively high sensitivity and another photoelectric converting element having a relatively low sensitivity. However, since the photoelectric converting elements which are arranged at spatially-separated positions are used as the high-sensitivity pixel and the low-sensitivity pixel, there is another problem that resolution is relatively lowered.
On the other hand, in order to acquire color image information, image signals having at least three color spectral sensitivities are required. When color image information is acquired by employing a solid-state imaging element, each of photoelectric converting elements corresponds to any one of at least three color spectral sensitivities. As a consequence, in such a case that color image information is acquired by using a single solid-state imaging element, image signals having respective spectral sensitivities are acquired from two-dimensionally different places, so that Nyquist domains (spatial frequency distributions) are not made coincident with each other. As a result, certain photographic subjects may conduct such a phenomenon as so-called “artificial color” and “color moiré.” There is a further problem that image qualities of photographed images are deteriorated.